Temperature alarm switch



May 5, 1953 J. T. GROTENHOUSE TEMPERATURE ALARM SWITCH Filed May 28,1951 INVENTOR m m M N m/ H N m T T A Patented May 5, 1953 James T.Grotenhouse, Oianggfiitw Iowa.

Applicatlonlvfay'28, 1951, sis-name: 228E689 1' Claim. (01. 200-140 Myinvention pertains to anral arm switch..

An object of my invention is to provide" a switch having an adjustablearrangement wherein the switch will operate below a pre-determinedpoint, and will further operate above a predetermined point, leaving acertain pre-selected range in which the alarm will not operate, theadjustment for the above purposes being relatively simple.

A further object of my invention is to provide the above mentioned in aneconomical construction.

With these and other objects in view, my invention consists in theconstruction, arrangement, and combination of the various parts of mydevice, whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claim, and illustrated in theaccompanying drawings, in which:

Figure 1 is a plan view of the switch base with the cover being removed,

Figure 2 is a sectional elevation of the switch and casing, and

Figure 3 is a detail.

My invention contemplates the provision of a switch which is responsiveto temperature conditions for use in brooders, or other locations andwhich switch will operate an alarm at predetermined temperatures, andyet leaving a certain range of temperature which will not operate thesaid alarm.

I have used the character In to designate the base of the switch, thecharacter ll indicating a suitable outer casing having the openings l2.

Attached to the base Ill are the members l3 to which is pivoted at I 4the U-shaped lever I5. Pivoted at I6 to the lever I is a furtherU-shaped lever ll which includes the transverse bar l8 attached thereto,to which is secured the spring H! which is attached at to the base l0.The member I! includes an opening 2| through which the spring I 3 canpass. A holder member 22 is secured to the base Ill and mounted in themember 22 is a micro-switch 23 which is suitably connected to any alarmcircuit which switch includes the button 24, the switch being normallyclosed and completing the circuit when the button 24 is in its upperposition.

Threadably engaging the top wall 25 of the member I5 is the verticallypositioned stud 26 having the knurled end 21 and the lock-nut 28, thelower end 29 of the stud 26 being adapted to engage the upper end 30 ofthe temperature responsive bellows 3|, which expands according to thetemperature.

which is adapted to bear against the lower wall of the lever ll asshown, the stud 32 having the knurled end 34 and lock-nut 35. The holdermember 22 includes the inner flange 36 having the upper edge 31.

The device operates in the following manner.

The stud 26 is provided for the purpose of establishing the alarm pointbelow a pre-determined temperature. For instance as shown in Figure 2the alarm circuit is open, assuming that the end 30 of the bellows 3|has just contacted the lower end 29 of the stud 26, this causing thelever member [5 to pivot upwardly and at the same time causing thespring l9 to pivot the member l1 downwardly providing means fordepressing the button 24 and keeping the circuit open. At anytemperature lower than this the outer end 38 will swing upwardly out ofengagement with the button 24 due to the fulcrum action at the point 31,thereby operating the alarm.

When the temperature increases beyond a predetermined point, since themember I! will abut against the end 33 of the stud 32, the bellows 3|will carry the entire unit upwardly as shown in Figure 3, therebyoperating the alarm also. It will be noted that the adjustablepositioning of the stud 32 provides any desired variation of temperaturerange within which the alarm will not be operated as will now beexplained. For instance if the stud 32 is rotated, bringing the point 33to a higher level, there will correspondingly be a longer range ofaction of the lever member I! as it fulcrums over the edge 31, therebyproviding non-operation of the switch, or in other words maintaining theswitch in opened position for a relatively longer interval.

Correspondingly, by rotating the stud 32 downwardly the lever actionwill not be over as long a period of time, thereby efiecting a shortertemperature range of non-operation. In this manner, the heated structurecan be maintained at a certain temperature range without operating thealarm, beyond which point however the alarm will operate.

It should be noted that the spring H! has the tendency of pulling theend 38 downwardly at all times.

It will now be noted that I have provided all of the advantagesmentioned in the objects of my invention with further advantages beingreadily apparent.

Some changes may be made in the construction and arrangement of theparts of my invention without departing from the real spirit and purposeof my invention, and it is my intention to cover by my claim anymodified forms of structure or use of mechanical equivalents which maybe reasonably included within their scope.

I claim as my invention:

A temperature alarm switch comprising an expansible temperatureresponsive member, a pivoted lever, a vertically positioned lengthenedstud I threadably engaged with said lever, the lower terminal 'of saidstud being adapted to engage said temperature responsive member at apre-determined temperature, and whereby adjustable movement of said studwill correspondingly vary member upon which said further lever fulcrumsincidental upon movement of said levers, means for adjustablypositioning said further lever to maintain said switch button in switchopening position at a predetermined interval including a further studthrea'dably engaging said pivoted lever, the lower terminal of saidfurther stud being adapted to engage the other end of said furtherlever, a base member, a spring attached between said base member andsaid further lever. adjustablepositioning of said further studvertically causing said switch to be opened during said predeterminedinterval corresponding to the fulcruming interval between said furtherlever and said flange.

JAMES T. GROTENHOUSE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,123,672 Du Bois July 12, 1938 2,357,878 Crew Sept. 12, 1944

